Improvement in bridges



T. MULL-IN.

BRIDGE.

No. 192,450. Patented June 26,1877.

INVENTUB BY I N. PETERS. PHOTO-LPNOGRAFNER, WAsKINGTDN, D. Cv

STATES PATENT rrron THOMAS MULLIN, OF MILLERSBURG, IOWA, ASSIGNOR TO HIMSELF AND WILLIAM H. ROLLER, OF SAME PLACE.

IMPROVEMENT IN BRIDGES.

Specification forming part of Letters Patent A e-192,450, dated June 26, 1877 application filed May 21,1877.

To all whom it may concern Be it known that l, THOMAS MULLIN, of Millersburg', Iowa county, Iowa, have inrented a new and Improved Bridge, of which the following is a specification Figure 1 is a side elevation of a bridge containing my improvement; and Fig. 2 is a vertical section on line a: at, Fig. 1. I

In bridges as ordinarily constructed the timbers give out first at the point Where the joist-bearers are secured to the stringers, as it is at this point that the water is retained, causing the speedy decay of the timbers.

To obviate this difficulty is the object of my invention.

In the drawing, A A are the trusses of an ordinary wooden bridge. 13 B are the chords or stringers, and B B are the floor-beams or joist-bearers, which are supported by rods 0, that run upward through the truss. Upon each side of the stringer B notches a are formed. The straight side of these notches is on a line with the vertical face of the stringer, and the boards that are used in covering the trusses are allowed to project slightly below the under surface of the stringer, for the purpose of carrying water below them.

The notches a are inclined downward each way from the center of the beam, so that no water can remainin them.

Notches similar to the notches a are also made in the abutments of the bridge, so that the stringers B are protected throughout their entire length.

The sides of the notches a are coated with paint or other water-proof material.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- In a bridge, the combination of the stringers B with the floor-beams B, having notches a a at the junctions of said stringers and beams, as shown, and for the purpose set forth.

THOMAS M ULLIN.

\Vitnesses:

WILLIAM Toovnr, A. J. Mon-arson. 

